Introduction

Breast feeding should be encouraged by education throughout pregnancy and the puerperium. Mothers should be told the benefits of breast feeding - it is emotionally satisfying, promotes mother-infant bonding, is economical, and gives significant immunity to the infant. The period of amenorrhea associated with frequent and consistent breast feeding provides some (though not completely reliable) birth control until menstruation begins at 6-12 months postpartum or the intensity of breast feeding diminishes. If the mother must return to work, even a brief period of nursing is beneficial. Transfer of immunoglobulins in colostrum and breast milk protects the infant against many systemic and enteric infections. Macrophages and lymphocytes transferred to the infant from breast milk play an immunoprotective role. The intestinal flora of breast-fed infants inhibits the growth of pathogens. Breast-fed infants have fewer bacterial and viral infections, less severe diarrhea, and fewer allergy problems than bottle-fed infants and are less apt to be obese as children and in adult life.

Frequent breast feeding on an infant-demand schedule enhances milk flow and successful breast feeding. Mothers breast feeding for the first time need help and encouragement from providers, nurses, and other nursing mothers. Milk supply can be increased by increased suckling and increased rest.

Nursing mothers should have a fluid intake of over 2 L/d. The United States RDA calls for 21 g of extra protein (over the 44 g/d baseline for an adult woman) and 550 extra kcal/d in the first 6 months of nursing. Calcium intake should be 1200 mg/d. Continuation of a prenatal vitamin and mineral supplement is wise. Strict vegetarians who eschew both milk and eggs should always take vitamin B12 supplements during pregnancy and lactation.

Effects of Drugs in a Nursing Mother

Drugs taken by a nursing mother may accumulate in milk and be transmitted to the infant (Table 18-4). The amount of drug entering the milk depends on the drug’s lipid solubility, mechanism of transport, and degree of ionization.

Suppression of Lactation

A. Mechanical Suppression
The simplest and safest method of suppressing lactation after it has started is to gradually transfer the baby to a bottle or a cup over a 3-week period. Milk supply will decrease with decreased demand, and minimal discomfort ensues. If nursing must be stopped abruptly, the mother should avoid nipple stimulation, refrain from expressing milk, and use a snug brassiere. Ice packs and analgesics can be helpful. If suppression is desired before nursing has begun, use this same technique. Engorgement will gradually recede over a 2- to 3-day period.

B. Hormonal Suppression
Oral and long-acting injections of hormonal preparations were used at one time to suppress lactation. Because of their questionable efficacy and particularly because of associated side effects such as thromboembolic episodes and hair growth, their use for this purpose has been abandoned. Similarly, lactation suppression with bromocriptine is to be avoided because of reports of severe hypertension, seizures, strokes, and myocardial infarctions associated with its use.

Ito S: Drug therapy for breast-feeding women. N Engl J Med 2000;343:118.

Zembo CT: Breastfeeding. Obstet Gynecol Clin North Am 2002; 29:51.